— Shashwat DC
As the earth shook, quaked and trembled in Nepal on April 25, 2015, thousands were killed in a matter of minutes, caught under the rubble of the fallen debris of homes and buildings. Measuring 7.8 on the Richter scale, the earthquake made the earth shiver for around half a minute, flattening almost everything in the Kathmandu valley. This quake was the largest one in the region in the past 8 decades; and the last big quake that took place was back in 1934. So far over 3000 people are reported to have died across Nepal, India, China (Tibet) and Bangladesh and the toll is expected to rise as more bodies are pulled out of the debris, and all the people that are presumed to be missing are accounted for.
Earthquakes are major cataclysmic events that occur because of tectonic plates pushing against each other. Across the fault lines, where these plates clash, energy keeps building up overtime and is dissipated in the form of an earthquake at regular intervals of times. These fault lines lie across the world, and the quake caused in Nepal was along the 1,400-mile Indo-Eurasian fault line, with the India plate pushing its way up against the Eurasian plate at a rate of about 5 centimetres, or approx 2 inches, a year. This is why the whole Himalayan plateau is prone to earthquakes, and this is what caused the latest devastation in Nepal.
Events like earthquakes are rarer and unpredictable, and have always confounded the scientific community. While we can’t pinpoint the triggers, we do know the science of what and how it is caused. And one thing we are sure of – the reasons are too big and to multifarious to be pinpointed at one direction. Even in the ancient times, the unscientific man knew that earthquakes were different from rest of the events (which could be blamed to a certain deity or another), hence even the myths were all so very different from the one about serpents changing loads to the giant (on whose head the earth rests) who goes on to turn his head.
Yet, there is one theory or linkage that is much debated, but cannot be truly debunked, namely the connection between earthquakes and climate change. Scientists across the globe are researching to find if there is a direct (or a discrete) connection between the two. While the connection is tenuous at the moment, the scientific community is now looking at various clues and exploring if climate-change related events could be offsetting cataclysms like earthquakes or Tsunamis. Bill McGuire, who is currently Professor of Geophysical and Climate Hazards at UCL, examined the link between climate-change and earthquakes and published a paper (or rather a book on the same). In “Waking the Giant: How a changing climate triggers earthquakes, tsunamis, and volcanoes“, he pored over the geological history of the planet and reached a conclusion that events like earthquakes and tsunamis are on the rise. The central idea is that melting ice-caps and rising sea-levels redistribute weight over continental fault-lines (like the one in Nepal) and thereby influence disasters like earthquakes or volcanoes.
But as for climate change affecting earthquakes, there are tentative hints of some links. Changing ice caps and sea-level redistribute weight over fault lines, which could potentially have an influence on earthquake occurrences. No studies have quantified the relationship to a high level of detail though, so recent earthquakes should not be linked with climate change. About 20,000 years ago, with global temperatures some 6 degrees milder and ice blankets spread all across Europe and North America, the earth presented a very different picture. The sea-level since that time has risen by some 130 metres and has been growing rapidly. Could this be one of the factors (mind you, not the only one) that influences such events?
While there will be many who would readily debunk the very discussion as hearsay or bunkum, the fact remains that catastrophic events like earthquakes and tsunamis are indeed influenced by the man’s hand. Take the case of the 1967 earthquake in Koynanagar (Maharashtra) which was induced by the construction of the Koyna dam. Earthquakes and tremors caused by human activity that alters the stresses and strains on the Earth’s crust are termed as induced seismicity. According to researchers, the 2008 Sichuan earthquake, which caused approximately 68,000 deaths, was caused by the construction and filling of the Zipingpu Dam that could have triggered the earthquake. Many scientists have warned that construction of dams in such seismic zones like the Tehri Dam or even the Three Gorges Dam will result in huge earthquakes in the days to come.
While the jury is still not out on the fact that anthropogenic climate-change has any influence on natural disasters, the fact remains that the damages caused by such events are exacerbated by the work of man. For instance, the floods of Uttarakhand in 2013 caused much havoc largely due to the manner in which settlements were made across the length of the rivers flowing through the state. Similarly, the floods in Kashmir were much severe since the natural flow of water has been constricted by unplanned and often illegal construction.
And while the link of man to causation aspects is disputed, there is no dispute on the link to destruction caused in the wake of such events. It is pretty obvious that the destruction caused by such events is often directly related to mankind’s increasing footprint. The last major earthquake to strike Nepal in 1934 (8.2 magnitude) was some 3.5 times more devastating than the current one (7.8). Yet, the current has caused more damage (relatively) simply because of the hap-hazard urbanisation that has happened over the ages. The mounds of rubble everywhere are a stark reminder of the monumental failure of building prudently in seismic zones.
With the Himalayan glaciers on a constant retreat (not as much as the IPCC reported) creating giant lakes, or the scores of dams being built to harness hydro-power, the frequency of such cataclysmic events is going to only increase. And, the naysayers might well turn into an ostrich and bury their heads in sand, but the severity and the finality of the situation can no longer be denied.
The essence of the argument was brilliantly captured by Bill, when he wrote in the Guardian.
“If we think about climate change at all, most of us do so in a very simplistic way: so, the weather might get a bit warmer; floods and droughts may become more of a problem and sea levels will slowly creep upwards. Evidence reveals, however, that our planet is an almost unimaginably complicated beast, which reacts to a dramatically changing climate in all manner of different ways; a few – like the aforementioned – straightforward and predictable; some surprising and others downright implausible. Into the latter category fall the manifold responses of the geosphere. The world we inhabit has an outer rind that is extraordinarily sensitive to change. While the Earth’s crust may seem safe and secure, the geological calamities that happen with alarming regularity confirm that this is not the case.”
Tough times lie ahead for all those on the Blue Marble, and the earlier we come to terms with it and start taking action, the better it will be for all.